The broad objective of the proposed research is to determine whether the catalytic function of flavin is restricted to oxidation-reduction reactions and to seek a better understanding of the mechanism of electron transfer in reactions where the coenzyme functions as a redox-active catalyst. The role of flavin in non-redox reactions will be investigated in studies with oxynitrilase which seek to discriminate between the established structural function of the coenzyme and the possibility that the coenzyme might directly assist in the catalytic reaction. Studies with glycolate oxidase will be conducted to evaluate the mechanism of hydrogen transfer during oxidation of alpha-hydroxy acids. The proposed studies involving both glycolate oxidase and oxynitrilase, which exhibits properties similar to oxidase enzymes, seek to evaluate the role of oxygenated flavins as reaction intermediates. The proposed research with these enzymes will involve spectroscopic, kinetic and structural analysis of reactions involving use of substrate analogues and modified flavin derivatives.